The hexose transport mechanism of isolated rat adipocyte plasma membranes will be identified, isolated and characterized biochemically by means of (a) selective double-labeling masking techniques using radioactive glutathione-maleimides, (b) reconstitution of stereospecific D-glucose transport in liposomes prepared from detergent-extracted adipocyte membranes and (c) application of antibodies to the hexose transport protein of human erythrocyte membranes. The effects of insulin on the membrane components of the hexose transfer will be determined. The biochemical information will be integrated with the results of flux studies to develop a useful molecular model of the hexose transport and the mechanism of regulation by insulin. Hexose transport protein(s) will be quantified in other insulin-sensitive tissues and in control and diabetic rats.